Previous year questions: The Living World

Previous year questions: the living world

All ten items below are from the official NCERT Exemplar Problems in Biology for Class 11. The exemplar does not print marks against each question, so the marks shown here follow the answer length the question asks for: one mark for a single fact, two marks for a short answer, three marks for a reasoned answer, and five marks for a long answer with an example. Each heading names the exemplar chapter and the question number inside its section.

Q1 (NCERT Exemplar, 1 mark)

NCERT Exemplar Class 11 Biology, Chapter 1, Multiple Choice Questions, Q10. Match the items of Column I with Column II and choose the correct option. Column I: A Family, B Kingdom, C Order, D Species, E Genus. Column II: i tuberosum, ii Polymoniales, iii Solanum, iv Plantae, v Solanaceae.

Answer: The correct option is A-v, B-iv, C-ii, D-i, E-iii. Family matches Solanaceae, kingdom matches Plantae, order matches Polymoniales, species matches tuberosum, and genus matches Solanum. The pairs follow the rank each word belongs to: Polymoniales is an order, Solanaceae a family, Plantae a kingdom, and tuberosum the specific epithet of potato.

Q2 (NCERT Exemplar, 2 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Very Short Answer Type Questions, Q5. Amoeba multiplies by mitotic cell division. Is this growth or reproduction? Explain.

Answer: The event counts as both. The parent cell divides and the number of cells rises, so the individual has grown. The division also produces two independent amoebae from one, which is reproduction by fission. In a single-celled organism the same division serves both purposes, because the body of the parent is also the reproductive unit. In a many-celled organism the two processes are separate, so the distinction is easier to see.

Q3 (NCERT Exemplar, 2 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Very Short Answer Type Questions, Q6. Define metabolism.

Answer: Metabolism is the sum of all the chemical reactions that take place in a living cell or body. It has two sides. Anabolism builds complex molecules from simpler ones and uses energy, while catabolism breaks complex molecules into simpler ones and releases energy. Both types of reaction can run in one cell at the same time, and no living organism is without them.

Q4 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Short Answer Type Questions, Q1. A ball of snow rolled over snow increases in mass, volume and size. Is this comparable to growth as seen in living organisms? Why?

Answer: The snowball does increase in size, but the change comes from snow sticking to its outside, so it is not growth in the biological sense. A living organism grows from inside, because its cells divide and the new cells add to the body from within. The snowball also has no organised cellular structure, no metabolism and no capacity to reproduce. The increase in size is therefore an accumulation of material, and it would stop the moment no more snow is added.

Q5 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Short Answer Type Questions, Q2. In a habitat we have 20 plant species and 20 animal species. Should we call this diversity or biodiversity? Justify.

Answer: The correct word is biodiversity. Biodiversity is the number and variety of organisms present in a place, and here that includes both plant and animal species, so the term covers the whole set. Diversity by itself is a broader word that can describe any kind of variation, and it does not specify the biological kinds being counted. Since the count lists species of plants and animals together, biodiversity is the precise term for what has been measured.

Q6 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Short Answer Type Questions, Q3. The International Code for Botanical Nomenclature provides a code for plant classification. Give the hierarchy of units a botanist follows and mention the suffixes used for the units.

Answer: The botanical hierarchy from the lowest unit upward is species, genus, family, order, class, division. Division holds the rank that phylum holds in the animal system. The suffix changes with the rank in the printed examples: Solanaceae is a family name and ends in -aceae, while Polymoniales is an order name and ends in -ales. The suffix is a quick check on the rank of a name, because the code fixes each rank so that the same ending does not stand for two different ranks.

Q7 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Short Answer Type Questions, Q7. A plant may have different names in different regions of the country or the world. How do botanists solve this problem?

Answer: Botanists solve the problem by naming the plant under the binomial system and the botanical code. The specimen is first identified by describing its features and comparing them with named specimens, published descriptions and keys. Once the identity is settled, the plant receives a scientific name of two parts, and that name is the same for every botanist in the world. A local name can still be recorded beside the scientific name, but the scientific name is the one used in publications and records.

Q8 (NCERT Exemplar, 3 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Short Answer Type Questions, Q8. Brinjal and potato belong to the same genus Solanum but to two different species. What defines them as separate species?

Answer: The two plants belong to one genus because they share a set of fundamental features that place them together. They are separate species because each has distinct morphological characters that are stable and inherited, and those characters do not merge the two into one group. A species is recognised by a group of individuals with fundamental similarities that can be told apart from closely related species. Since brinjal and potato differ consistently in form while both sit inside Solanum, taxonomists keep them as two species of the one genus.

Q9 (NCERT Exemplar, 5 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Long Answer Type Questions, Q1. What is meant by living? Give any four defining features of life forms.

Answer: Something is living when it has a cellular organisation in which chemical reactions run continuously and it responds to its surroundings. Four defining features carry the definition. Growth takes place by division of cells, so the body adds its own material. Reproduction produces young ones of the same kind, which keeps the species going. Metabolism includes all the building and breaking reactions in the cell, and no living organism lacks it. Consciousness is the ability to sense and respond to the environment, and it is the feature that marks the living most sharply. Movement and size are useful observations, but neither one on its own defines life, because a rooted plant is alive without moving and a growing crystal is not alive.

Q10 (NCERT Exemplar, 5 marks)

NCERT Exemplar Class 11 Biology, Chapter 1, Long Answer Type Questions, Q5. Define a taxon. What is meant by taxonomic hierarchy? Give a flow diagram from the lowest to the highest category for a plant and an animal. What happens to the number of individuals and the number of shared characters as we go up the hierarchy?

Answer: A taxon is a group of organisms treated as a unit of classification at a rank. The taxonomic hierarchy is the arrangement of these ranks in order, with each higher rank holding one or more groups of the rank below it. For a plant such as mango the order is species Mangifera indica, genus Mangifera, family Anacardiaceae, order Sapindales, class Dicotyledonae, division Angiospermae, kingdom Plantae. For an animal such as man the order is species Homo sapiens, genus Homo, family Hominidae, order Primata, class Mammalia, phylum Chordata, kingdom Animalia. As the hierarchy is climbed, the number of individuals covered by a rank rises, since more organisms share a broader group. The number of shared characters falls, because each rank upward keeps only a part of the features that define the rank below it. The two changes are the same fact seen from two sides.